Phase and miscibility behavior of binary lipid systems

Abstract

Differential scanning calorimetry was applied to study the phase diagrams of the following binary lipid systems: myristic acid (C13COOH) / pentadecanoic acid (C14COOH); palmitic acid methyl ester (C15COOMe) / heptadecanoic acid methyl ester (C16COOMe); palmitic acid methyl ester (C15COOMe) / stearic acid methyl ester (C17COOMe); palmitic acid methyl ester (CIsCOOMe) / arachidic acid methyl ester (C19COOMe). A distinct succession in the phase diagram types and phase regions was observed, according to the chemical structure of the mixing components. In the systems C13COOH/C14COOH; C15COOMe/C16COOMe and C16COOMe/ C17COOMe, both components are completely miscible in the low-and high-temperature phase. Contrasting with these three binary lipid systems, the system C15COOMe/ C14COOMe shows complete miscibility only in the high-temperature phase, but almost complete demixing in the solid state. In the phase diagram an incongruent melting "1:1 complex" is built up. This "complex" forms an eutectic mixture with the phase of C15COOMe and a peritectic system with C19COOMe.

Correlating the Cloud Point of Biodiesel to the Concentration and Melting Properties of the Component Fatty Acid Methyl Esters

“…The calculated intersection of SLE curves for MeC18 and MeC20 occurred at y 1 = 0.8865 and T f = −1.67 °C, corresponding to a mole ratio (x C18 /x C20 ) = 4.22. Such transitions have been observed for binary mixtures of pure MeC16/MeC18 26,42,43 and MeC16/ MeC20. 43,44 The behavior discussed earlier for experimental data in Figure 3c may have been affected by intersecting SLE curves for controlling FAME in this admixture system.…”

Evolution of the Study of Phase Diagram of Binary and Ternary Mixtures Involving Fatty Acid Esters

“…Predictive models are studied and evaluated for the measured mixtures by almost all the aforementioned authors, with the exception of older articles [ 27 , 28 , 29 , 38 , 39 , 40 ] and in the work of a few more recent authors evaluating the use of FAE as PCM [ 29 , 48 , 50 ]. Scientists researching on biodiesel are the ones who extensively report the comparison of experimental results with theoretical models, using mainly UNIQUAC [ 31 , 32 , 34 , 37 , 42 , 43 , 44 , 49 , 55 ], UNIFAC [ 30 , 31 , 52 , 53 , 55 , 58 , 59 ], Flory–Huggins (especially Robustillo’s team) [ 35 , 45 , 46 , 47 , 52 , 53 , 55 , 58 , 59 ] and ideal models, based on Schraeder’s equation [ 36 , 43 , 44 , 49 , 52 , 53 , 54 , 55 , 58 , 59 ].…”

“…A similar tendency to that of fatty acid ethyl esters’ mixtures is observed concerning the study of phase diagrams of binary mixtures of FAME through the years. Some references from the second half of 20th century can be found [ 38 , 39 , 40 ], and some binary mixtures of FAME were reported in one of the articles already mentioned [ 29 ], but that of Imahara et al [ 31 ] can be considered the first work specifically studying the cloud point of binary mixtures of fatty acid methyl esters. The solid–liquid equilibrium of eight mixtures is reported, and the cloud point line is predicted using the same model found in [ 29 ].…”

The effects of dry O3, SO2 and NO2 on reconstituted epicuticular wax tubules

“…As all these compounds are known to crystallize as platelets (Chambers, Ritchie & Booth, 1976) the question arises why only smooth films were observed. Binary mixtures of C,, and C^^â lkanoic acids are known to form mixed crystals (Small, 1984;Dorfler & Pietschmann, 1990) whereas mixtures of acids that differ in chain length by six or more carbons tend to separate into neat crystals (Small, 1984). Thus, at equilibrium, the quaternary fatty acid mixtures produced by long-term fumigation of nonacosan-10-ol might separate into two distinct types of crystallites of either Cg/Cj^ or C19/C20 acids.…”